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Date: Mon, 05 Feb 2001 18:07:40 -0600 (CST)
From: "Jonathan R. Wagner" <znc14@TTACS.TTU.EDU>
To: David Marjanovic <David.Marjanovic@gmx.at>
Cc: PhyloCode@ouvaxa.cats.ohiou.edu
Subject: Re: Another example
At 10:25 PM 2/5/01 +0100, David Marjanovic wrote:
>Ornithurae has seen lots of different usages over time,
Unfortunately, I personally do not feel that the phylocode can take
on such divisive taxonomic issues in an example. Perhaps I am alone in this.
Note that I specifically did *not* recommend a solution to the Mammalia
issue, indeed all I suggested was that an apomorphy-based definition was
probably NOT the answer. And, for all the picking I do on Ankylopollexia, I
just modify the currently published definition slightly.
FYI: I am a crown-cladist whenever possible.
>I'd suggest an apomorphy-based definition which would at present have the same
>contents as Pygostylia -- or just drop it, because it has caused so much
>confusion and has been used as sister group of demonstrably para or
>polyphyletic "Sauriurae".
As I told Dr. Hillis, I do not advocate the use of apomorphy-based
clades, and I especially do not advocate it once a the name has been clearly
associated with another type of definition (as a personal preference, I find
it less distasteful if switched between node- and stem-based definitions).
Ornithurae, although not very old, has been used extensively, according to
several different "concepts," and has been "defined" twice* (as a
stem-based-, and as a node-based name). Regardless on one's take on priority
prior to the establishment of the PhyloCode, it seems clear that adding an
additional definition, of a third class, is unwieldly.
In any event, the name has taken on a "life of its own" (as I put
it, so tritely), in that, although its placement varies, sometimes
independently of one's crown group policy, it inevitably appears in any
discussion of early birds. Dropping it would therefore be somewhat
irritating, it seems that everyone agrees that, whichever position it
occupies, that position needs a name. Eliminating this name requires then
the coining of TWO new names, as opposed to one. I don't know what will
eventually happen, maybe a coin will be flipped.
Jonathan R. Wagner
* Actually, at least three times, Gauthier 1986, Padian Hutchinson and Holtz
1999, and Sereno 1999. The first and last definitions are operationally
identical, within their respective contexts... the situation is yet another
example of why species make the best specifiers.
--------------------------------------------------------------------------------
Jonathan R. Wagner, Dept. of Geosciences, TTU, Lubbock, TX 79409-1053
"Why do I sense we've picked up another pathetic lifeform?" - Obi-Wan Kenobi